Search Results (301)

Currently, safe alternatives with very low toxicity and good antimicrobial activity are being sought to replace chemical compounds that can be harmful to animal and human health. For this reason, this study evaluated the safety and biofunctional microbiocidal potential of an extract composed of thymol and eucalyptol. Toxicity tests showed low toxicity in both chickens (2000 mg/kg bw) and Artemia salina (EC₅₀ = 2003 mg/L) and Daphnia magna (EC₅₀ = 87 mg/L), indicating a safe usage profile. Oxidative stress biomarkers (nitrite and MDA) and antioxidant enzymes (SOD and catalase) improved in treated chickens at 20 days of age. The hematological and biochemical parameters of the treated birds showed normal values similar to those of the control group chickens, with better protein levels and lower AST levels. Histology of the kidney, intestine, and liver showed no changes in any group, confirming the absence of systemic adverse effects. At the molecular level, an improvement in the expression of tight junction proteins (claudin and occludin) was observed, suggesting a strengthening of the intestinal barrier integrity. Finally, the extract demonstrated an antimicrobial effect (E. coli, C. perfringens, Salmonella sp. and Pseudomonas sp.) comparable to that of organic acids commonly used as food preservatives, positioning it as a promising alternative in applications. Full article

Bacillus species represent promising alternatives to antimicrobial growth promoters, offering potential benefits for productivity and gut health in broilers. This study aimed to isolate Bacillus strains with inhibitory activity against Clostridium perfringens and evaluate their probiotic potential through in vitro and in vivo approaches. In Experiment 1 (in vitro), five strains—B. siamensis C66, B. tequilensis Y7, B. velezensis L15, B. amyloliquefaciens C271, and B. siamensis C377—were isolated and assessed for stress tolerance, digestive enzyme production, and antimicrobial activity. All strains demonstrated high survival rates under acid and bile stress, produced multiple digestive enzymes, and significantly inhibited the growth of C. perfringens. In Experiment 2 (in vivo), 630 day-old male Arbor Acres broilers were randomly assigned to one of seven dietary treatments for 42 days: a negative control (CON, basal diet), a positive control (ANfT, basal diet supplemented with 6.4 g/t virginiamycin), and five groups receiving basal diet supplemented with one of the Bacillus strains at 1 × 10¹¹ CFU/kg. Among these, B. amyloliquefaciens C271 significantly increased breast muscle yield (p < 0.05), improved jejunal morphology—evidenced by increased villus height and villus height-to-crypt depth ratio (p < 0.05)—and positively modulated cecal microbiota composition compared to the CON group. These findings demonstrate that the newly isolated B. amyloliquefaciens C271 possesses strong probiotic properties in vitro and promotes growth performance and gut health in broilers, suggesting its viability as an antibiotic growth promoter substitute. Full article

The objective of our study was to verify the intervention effect of Bacillus amyloliquefaciens SC06 on NE by constructing a C. perfringens-induced intestinal damage mouse model. A total of 40 mice were randomly assigned to four treatments: CON (basal diet), CP (basal diet + C. perfringens), SC06 + CP (basal diet + SC06 + C. perfringens) and SC06 (basal diet + SC06). Our findings indicated that SC06 supplementation was effective in maintaining the integrity of the intestinal barrier, enhancing the antioxidant capacity of the intestine, reducing the generation of an inflammatory response, and suppressing enterocyte apoptosis in the presence of C. perfringens. Furthermore, SC06 supplementation enhanced the prefoliation of intestinal stem cells (ISC) and prompted their differentiation into goblet cells and Paneth cells. Moreover, our findings indicate that SC06 promotes the proliferation of C. perfringens-induced jejunum organoids and the expression of genes and proteins associated with ISC differentiation and regeneration. The mechanism by which SC06 modulates ISCs has been validated, and the results align with those obtained in vivo. In conclusion, the findings demonstrated that SC06 stimulates the proliferation and differentiation of ISCs through the activation of the Wnt/β-catenin signaling pathway, thereby accelerating epithelial regeneration and repair. Full article

Clostridium perfringens is a spore-forming bacterium that causes food poisoning. Given the high heat resistance of its spores, natural antimicrobial agents are considered as alternatives to thermal processing strategies to inactivate or eliminate such spores from food products. A high chitosan concentration (0.2%) can effectively inhibit the growth of C. perfringens spores in cooked chicken meat, whereas nisin cannot (even at concentrations four times higher than those permitted: 250 μM). However, nisin is an effective inhibitor when in combination with other preservatives. Therefore, we evaluated the inhibitory effects of a chitosan–nisin combination on the germination, outgrowth, and vegetative growth of C. perfringens spores in laboratory medium and chicken meat. Among many tested concentration combinations, a 0.025% chitosan and 0.075% nisin mixture was found to be the most effective for inhibiting spore germination and outgrowth in laboratory medium. Furthermore, a mixture of chitosan–nisin, at 0.025% each, blocked the vegetative growth of C. perfringens spores. However, four-times higher concentrations of chitosan–nisin (0.1% each) were required to effectively inhibit C. perfringens spore germination in chicken meat. Collectively, our results suggest that the combination of chitosan and nisin can be considered as an alternative approach to control C. perfringens spore germination in meat products. Full article

The current study aims to investigate the effects of additional valine and isoleucine in different necrotic enteritis (NE) challenge intensities. A total of 648 seven-day-old male Cobb 500 were allotted to nine treatments with six replicates. Two different NE intensity experiments (Exp-1 and Exp-2) were conducted. The five treatments for each NE experiment were as follows: (1) non-challenged shared control (NC), (2) NE challenge (NE), (3) 130% additional valine (VAL), (4) 130% additional isoleucine (ILE), and (5) 130% valine and isoleucine (MIX). In both experiments, all NE-challenged groups had decreased body weight gain compared to the NC group (p < 0.05). The ILE group in Exp-1 had further reduced body weight compared to the NE group on day 21 (p < 0.05). No significant differences were observed in intestinal permeability, jejunal NE lesion score, jejunal C. perfringens colony counts, jejunal morphology, jejunal gene expression levels, breast muscle yield, and body mineral compositions among all NE-challenged groups (p > 0.05). In conclusion, 130% additional valine and isoleucine hardly mitigated the negative effects of NE. Additional isoleucine may further worsen chicken growth performance, but this effect may vary depending on the intensity of the NE challenge. Full article

Background/Objectives: Bacillus probiotic mixtures have been used as a novel source of antimicrobial production. However, there is a need to emphasize the potential of co-cultured Bacillus strains and to understand the underlying mechanisms involved in their combination formulation. Methods: Bacillus strains BPR-11, BPR-16, and BPR-17, were cultured either as mono or multi-cultures. The bacterial growth and density were evaluated by measuring their optical density. The chemical profiles of their bioactive extracts were analysed by LC-MS, and their antimicrobial activity were tested against selected pathogens. Results: Our results reveal that co-cultured strains significantly increased bacterial growth, with an optical density level of, 2.67 which was significantly higher than the monocultures of BPR-11 (2.24), BPR-16 (2.32), and BPR-17 (2.22). Furthermore, the ethyl acetate extracts from these bacterial cultures showed that the combined co-culture (F1) exhibited the highest antimicrobial activity, with MICs of 25 µg/mL against C. perfringens, E. coli, and S. aureus, and 50 µg/mL against P. aeruginosa and S. enterica. In contrast, the monocultures BPR-16 and BPR-17 showed moderate activity with MICs of 50 µg/mL against C. perfringens, E. coli, and S. aureus, and 100 µg/mL against P. aeruginosa and S. enterica. BPR-11 had the lowest antimicrobial activity, with MICs of 100 µg/mL against C. perfringens, E. coli, and S. aureus, and no activity against P. aeruginosa and S. enterica. Metabolite profiling showed that the extract from the co-culture had a marked increase in the production of antimicrobial metabolites, including C₁₃-C₁₆ surfactin C. Lastly, the metabolism study of surfactin C analogues suggested that they were highly stable (99%) when incubated with cytochromes P450 over 120 min. Conclusions: Together, these findings highlight the potential for multi-strain co-culturing to develop new antimicrobials and provide valuable insights into the synergistic effects for antimicrobial production. Full article

Background: Clostridium perfringens (C. perfringens) type A is a major cause of enteritis in farmed and wild deer populations, leading to significant economic losses in the deer industry. This bacterium produces toxins that damage the intestine. Methods: In this study, we performed transcriptome analysis by establishing an intestinal circulation model of the intestines of fallow deer (Dama Dama) inoculated with C. perfringens type A versus those not inoculated with C. perfringens type A. In a further step, we determined the protein content of immunoinflammation-related molecules by ELISA and the antioxidant capacity of the intestine to investigate the molecular mechanisms of C. perfringens type A-induced enteritis. Results: Transcriptome analysis revealed significant enrichment of pathways related to the haematopoietic system, oxidative stress, the immune system and intestinal tight junctions. Additionally, C. perfringens α-toxin enters the intestine and may be recognized by TLR6, activating the immune system, increasing the secretion of various cytokines and inflammasome components, inducing oxidative stress and damaging the intestine. Conclusions: This study provides a comprehensive transcriptomic basis for understanding the selective differential expression of genes in deer enteritis induced by C. perfringens type A and provides a broader guide for finding therapeutic approaches to deer enteritis. Full article

Background/Objectives: Lactobacillus kefiranofaciens HL1, isolated from kefir, exhibits antioxidant and anti-aging activities, defined here as improved cognitive function and reductions in oxidative stress and inflammatory markers. However, its poor milk viability limits application. This study developed a novel fermented milk by co-culturing HL1 with Lactococcus lactis subsp. cremoris APL015 (APL15) to enhance fermentation and health benefits. Methods: HL1 and APL15 were co-cultured to produce fermented milk (FM), and fermentation performance, microbial viability, texture, and syneresis were evaluated. A D-galactose-induced aging BALB/c mouse model was used to assess cognitive function, oxidative stress, inflammation, antioxidant enzyme activity, and gut microbiota after 8 weeks of oral administration. Results: FM reached pH 4.6 within 16 h, with high viable counts (~10⁹ CFU/mL) for both strains. HL1 viability and texture were maintained, with smooth consistency and low syneresis. In vivo, FM improved cognitive behavior (Y-maze, Morris water maze), reduced oxidative damage (MDA), lowered IL-1β and TNF-α, and enhanced brain SOD levels. FM-fed mice exhibited increased short-chain fatty acid producers, higher cecal butyrate, and reduced Clostridium perfringens. Conclusions: The co-cultured fermented milk effectively delivers HL1 and provides antioxidant, anti-inflammatory, and anti-aging effects in vivo, likely via gut–brain axis modulation. It shows promise as a functional food for healthy aging. Full article

Necrotic enteritis, caused by Clostridium perfringens (C. perfringens) is a disease present worldwide and causes major economic losses. The re-emergence of the disease, in recent years, is mainly due to the ban of the usage of antibiotics as growth promoters in the EU. The aim of this study was to establish a reliable, robust challenge model. Ross hybrid broilers were divided into randomized groups: a positive and a negative control group, a group receiving antibiotic treatment and three groups fed with assorted feed supplements, all receiving the same basal diet. The birds in the treatment groups were vaccinated twice using a 10-times dose of an Infectious Bursitis live vaccine and the animals were challenged four times with a NetB toxin producing C. perfringens strain. The presence of clinical signs and body weight gain were monitored. At the end of the study necropsy was performed and the gut lesions were scored. During the experiment, clinical signs were absent in the negative control group and in the antibiotic treated group. The other animals displayed diarrhea and feather loss. These symptoms were the most pronounced in the positive control group. The gut lesion scores showed significant differences between the negative and positive control groups, with the former scoring the lowest. Based on these results, the challenge model establishment was successful and in this setup the assessment of the potency of feed additives is also possible. Full article

Necrotic enteritis (NE), caused by Clostridium perfringens, poses significant economic challenges to the global poultry industry. The widening ban on in-feed antibiotics in livestock production underscores the need for alternative strategies to combat NE. Deoxycholic acid (DCA), a secondary bile acid, has shown promise in NE mitigation. However, its protective mechanism remains largely unexplored. A total of 120 newly hatched, male Cobb broilers were randomly divided into four treatments to investigate the impact of DCA on host response and intestinal microbiome in both healthy and NE-infected chickens. The results demonstrated that the dietary supplementation of 1.5 g/kg DCA significantly improved animal survival, reversed growth inhibition, and alleviated intestinal lesions (p < 0.01). Furthermore, DCA selectively inhibited the NE-induced proliferation of C. perfringens and other pathobionts such as Escherichia and Enterococcus cecorum. Concurrently, DCA markedly enriched dominant lactic acid bacteria like Lactobacillus johnsonii in both the ileum and cecum of NE-infected chickens. However, DCA had a marginal effect on the jejunal transcriptomic response in both mock- and NE-infected chickens. Therefore, we conclude that DCA protects chicken from NE mainly through the targeted inhibition of pathobionts including C. perfringens, with minimum impact on the host. These findings elucidate the protective mechanisms of DCA, supporting its development as a promising antibiotic alternative for NE mitigation. Full article

This exploratory study presents the first metagenomic assessment of the gut microbiome in domestic cats from Cali, Colombia. Fecal samples were collected from 10 healthy, sterilized domestic cats, aged 8 months to over 2 years, with variation in sex (7 females, 3 males), diet (processed or raw), and outdoor access (5 with, 5 without). Using 16S rRNA gene metabarcoding and pooled shotgun metagenomic sequencing, the study characterized the taxonomic composition and functional potential of the feline gut microbiome. Dominant phyla included Bacillota and Bacteroidota, with substantial inter-individual variation. Peptoclostridium was the most consistently abundant genus, while Megamonas and Megasphaera showed higher variability. Shotgun analysis detected antibiotic resistance genes (ErmG, ErmQ) and virulence factors (pfoA, plc, colA, nanJ, nagI) in Clostridium perfringens, highlighting potential zoonotic risk. The composition of the gut microbiota was influenced primarily by diet and outdoor access, while age and gender had more moderate effects. The study concludes that lifestyle and environmental factors play a key role in shaping the gut microbiome of domestic cats. We recommend further longitudinal and larger-scale studies to better understand the dynamics of feline microbiota and their implications for animal and public health within a One Health framework. Full article

Background/Objectives: Natural products such as honey and propolis have been widely studied for their antimicrobial properties. Combining these substances has shown synergistic effects against foodborne pathogens and has also demonstrated promising results in previous applications on fermented meat products. This study evaluated the antibacterial potential of Spanish thyme (Thymus spp.) and chestnut (Castanea sativa) honeys, enriched with 10% ethanolic extract of propolis, against two major foodborne pathogens: Listeria monocytogenes and Clostridium perfringens. Methods: Antibacterial activity was assessed using broth microdilution assays and colony-forming unit (CFU) counts. The phenolic composition of the most active samples was characterized by LC-MS-Q/TOF and UPLC-PDA to identify and quantify the bioactive compounds. Results: All samples exhibited differential responses depending on the pathogen, with C. perfringens being the most susceptible. Propolis addition significantly enhanced the bactericidal response of honey against L. monocytogenes and C. perfringens (p < 0.05). This effect correlated with higher levels of antimicrobial phenolic compounds, particularly cinnamic acid derivatives, pinobanksin-3-O-hexanoside, sakuranetin, quercetin, and quercetin-3,7-dimethyl ether. Conclusions: These findings support the synergistic antibacterial potential of honey-propolis combinations, highlighting their application as natural preservatives for reducing the risk of foodborne diseases, as well as bioactive ingredients in nutraceutical formulations with antibacterial properties and additional health benefits. Full article

Utilizing deep eutectic solvents (DESs) combined with microwave-assisted extraction (MAE) provides a sustainable method for extracting bioactive compounds from the macroalgae Ascophyllum nodosum and Laminaria hyperborea. Two DES formulations, choline chloride/lactic acid (ChCl/LA) and sodium acetate/lactic acid (AcNa/LA), were evaluated under varying extraction conditions. For L. hyperborea, ChCl/LA at 150 °C for 10 min yielded a total phenolic content (TPC) of 15.34 mg GAE/g DW, with antioxidant activities measured by DPPH (34.55 mg TE/g DW) and ABTS (27.06 mg TE/g DW). Extending the extraction to 20 min at 130 °C increased the TPC to 19.12 mg GAE/g DW. A. nodosum exhibited higher bioactivity, with the TPC reaching 47.51 mg GAE/g DW under the same conditions. High-performance liquid chromatography (HPLC) identified significant phenolics such as 3,4-dihydroxybenzoic acid (678.05 µg/g DW) and vanillin (6718.5 µg/g DW). Antimicrobial assays revealed strong inhibition (zones > 20 mm) against Clostridium perfringens, moderate activity against Staphylococcus aureus, and selective activity against Escherichia coli. FT-IR confirmed the presence of phenolics, polysaccharides, and lipids. Thermal and structural characterization revealed that A. nodosum residue showed an amorphous structure, while L. hyperborea retained crystallinity with decomposition profiles indicating potential bioenergy potential. SEM images revealed significant cell wall disruption correlating with extraction efficiency. These results demonstrate DES–MAE as an effective, green strategy for producing high-value algal extracts and valorizing residual biomass for biotechnological applications. Full article

The increasing demand for sustainable protein sources highlights Hermetia illucens (Black Soldier Fly, BSF) as a promising alternative. However, microbiological safety remains a key concern. This study investigated the microbial diversity of BSF larvae, comparing two processing methods: (1) boiling followed by drying and (2) drying alone. Microbial diversity was assessed via 16S rRNA sequencing, while bacterial loads were quantified using culture-based methods on samples from a French company. A systematic review complemented this analysis by synthesizing the existing knowledge on BSF microbiota. The rearing conditions varied, with substrate pH ranging from 4.1 to 9.0 and ambient temperatures between 24.6 °C and 42.7 °C. Mesophilic bacteria, spores, and lactic acid bacteria reached up to 8.6, 7.7, and 8.5 log CFU/g in the substrates and larvae, while yeasts, molds, and sulfite-reducing bacteria remained below 4.8 log CFU/g. Boiling reduced most loads below detection thresholds, particularly for yeasts, molds, and ASR. Salmonella, Listeria monocytogenes, Cronobacter sp., and coagulase-positive staphylococci were absent, whereas Clostridium perfringens and Escherichia coli were variably detected. Metabarcoding showed shifts in composition, with Proteobacteria, Bacteroidota, Actinobacteriota, and Firmicutes (Bacillota and Clostridiota) dominating. Process 1 more effectively reduced the bacterial loads, though Bacillus and Clostridium remained. Campylobacter sp. detection in powders raises food safety concerns. Full article

Background/Objectives: Clostridium perfringens is a normal inhabitant of the intestinal tract of poultry, and it has the potential to induce cholangiohepatitis and necrotic enteritis (NE). The poultry industry suffers significant financial losses because of NE, and treatment becomes more challenging due to resistant C. perfringens strains. Methods: The antimicrobial and antibiofilm activities of cellulose nanocrystals/zinc oxide nanocomposite (CNCs/ZnO) were assesses against pan drug-resistant (PDR) C. perfringens isolated from chickens and turkeys using phenotypic and molecular assays. Results: The overall prevalence rate of C. perfringens was 44.8% (43.75% in chickens and 58.33% in turkeys). Interestingly, the antimicrobial susceptibility testing of C. perfringens isolates revealed the alarming PDR (29.9%), extensively drug-resistant (XDR, 54.5%), and multidrug-resistant (MDR, 15.6%) isolates, with multiple antimicrobial resistance (MAR) indices ranging from 0.84 to 1. All PDR C. perfringens isolates could synthesize biofilms; among them, 21.7% were strong biofilm producers. The antimicrobial potentials of CNCs/ZnO against PDR C. perfringens isolates were evaluated by the agar well diffusion and broth microdilution techniques, and the results showed strong antimicrobial activity of the green nanocomposite with inhibition zones’ diameters of 20–40 mm and MIC value of 0.125 µg/mL. Moreover, the nanocomposite exhibited a great antibiofilm effect against the pre-existent biofilms of PDR C. perfringens isolates in a dose-dependent manner [MBIC50 up to 83.43 ± 1.98 for the CNCs/ZnO MBC concentration (0.25 μg/mL)]. The transcript levels of agrB quorum sensing gene and pilA2 type IV pili gene responsible for biofilm formation were determined by the quantitative real time-PCR technique, pre- and post-treatment with the CNCs/ZnO nanocomposite. The expression of both genes downregulated (0.099 ± 0.012–0.454 ± 0.031 and 0.104 ± 0.006–0.403 ± 0.035, respectively) when compared to the non-treated isolates. Conclusions: To the best of our knowledge, this is the first report of CNCs/ZnO nanocomposite’s antimicrobial and antibiofilm activities against PDR C. perfringens isolated from chickens and turkeys. Full article